Introduction: Heparin is only fast acting anticoagulant drug available in the injectable form. Skin discoloration is an adverse and unpleasant outcome of subcutaneous heparin injection that is observed frequently and causes the patient both physical and psychological discomfort thus limiting the further sites for injection. It is therefore important that nurses use an injection technique that minimizes the incidence of adverse outcomes. This research is a quasi-experimental study carried out to determine the relation between duration of injection of subcutaneous heparin and extent of local skin discoloration at the Fatima and Shahid Beheshti cardiac hospitals, Shiraz, 2002 .
Methods: 167 patients were selected and sampling was done by selecting consecutive samples. Data collection was done by using a researcher-made check-list consisting of section of demographic characteristics and a section to record the extent of discoloration at 48 and 60 hours after injection. Data analysis was done by distributional index and parametric (paired-t test) and Bi-parametric (Mann witney-U and kruskal wallis).
Results: Extent of local skin discoloration was less in 30-second injection technique, so that the mean size at 48 and 60 hours after 10-second injection techniques (82.85 214.3,77.96 206 ,respectively) was more than the mean size at 48 and 60 hours after 30-second injection technique (40.53 148.11,44.41 175.51 respectively).There was a significant relationship between sex and size of discoloration (p<0.001),so that mean size in females in the 10-second and 30-second injection techniques at 48 and 60 hours after injection was more than that in males.
Conclusion: On the basis of results of this research, administering subcutaneous heparin injection over longer duration, especially in females reduces injection site discoloration.